Meter reading systems have been used by utility companies to assist in reading electric, water and gas meters in the home by various means which aim to reduce the utility company manpower required to make meter readings in sufficiently frequent intervals such that the homeowner is fairly accurately billed based on his actual consumption. In many instances, customers receive many estimated bills which are largely in error due to either the shortage of company readers in the field and/or the ability of the readers to enter the home. In the case of the delivery of oil to the homes, the human error often results in oil tanks being depleted, incorrect estimates of usage and the failure of the customer to call the fuel company to request delivery. On the other hand, inefficient operation often results from deliveries being made too frequently when not needed.
Attempts to eliminate some of these problems have been made by the water supply companies which connect electric meter reading devices in the home to make readings on a regular basis, such as once a day, and transmit the read data over telephone lines to a central computer which records and stores the readings. The electronic meter reading devices which use the telephone lines for providing readings on a regular basis are not economically advantageous due to the high cost of the meter reading devices and the frequent use of the telephone lines.
U.S. Pat. No. 3,842,208 to Paraskevakos discloses a device which automatically monitors a plurality of sensors, such as alarm devices, and which is activated by the sensors of alarm devices, such as burglar alarms, cardiac alarms and meters for gas and electricity. Electronic circuitry is disclosed connected to the telephone line and the alarm devices for seizing control of the telephone line even if it is currently in use in response to the input sensor circuits of the alarm devices being triggered. The devices disclosed in this patent provide automatic monitoring of a plurality of sensors which, when activated, seizes a telephone line even if such line is in use. This patent relates to the general monitoring of conventional sensor devices and the seizing of telephone lines, but does not solve the problems of providing a simple and accurate measuring means for detecting and signalling a predetermined inventory level of product in a tank and for communicating a prescribed or predetermined consumption of product in the tank. Also, this patent and other prior art monitoring systems do not provide a simple alarm system which determines the consumption of a product in a tank to an alarm level in a simple and accurate manner.
It is an object of the present invention to provide an alarm system for determining when a product in a tank located in a home, factory or other building has been depleted to a predetermined level and for automatically providing an alarm signal for causing replenishment of the product.
It is another object to provide an alarm system used in a home or office for determining when the consumption of a product in a tank has been depleted to a predetermined level, which system is simple and economically feasible to employ in the home or other building.
It is another object to provide a system for automatically signalling to the central office that it is time for replenishment of a tank in an office or other building without requiring the human intervention by the resident or occupant.
It is another object to provide an alarm system for signalling the time for replenishing a product stored in a tank in a home, office or other building which does not require costly and complex meter reading equipment, but does require the reporting of the consumption of the amount of product.
It is another object to provide an alarm system for indicating the consumption of oil or other liquid from a tank or pipeline, and which does not require monitoring or measuring of fluid levels in a tank.